Cytotactin, an extracellular matrix protein of neural and non-neural tissues that mediates glia-neuron interaction.

Abstract

An extracellular matrix protein, cytotactin, with widespread tissue distribution has been identified, isolated, and partially characterized. Cytotactin mediates glia-neuron adhesion in vitro, but unlike Ng-CAM, the neuron-glia cell-adhesion molecule, it is absent from neurons. Cytotactin was isolated from 14-day embryonic chicken brains as structurally related polypeptides of Mr 220,000, 200,000, and 190,000. These polypeptides were efficiently extracted in the absence of detergent and appeared to be disulfide-linked into higher polymers. Immunofluorescence staining with specific antibodies indicated that cytotactin is found in extracellular spaces and in basement membranes of a variety of non-neural tissues including smooth muscle, lung, and kidney. In the cerebellum, it appears on glial end-feet, on Bergmann glial fibers, and in extracellular spaces. The molecule is synthesized by glia and cells from smooth muscle, lung, and kidney. It is found at the surface of glia in culture in a cell-associated fibrillar pattern. A survey of the times and sites of its appearance during embryogenesis is consistent with the hypothesis that cytotactin is a cell-substrate adhesion molecule that may mediate cell migration in a site-restricted fashion.

Embryonic expression of tenascin‐X suggests a role in limb, muscle, and heart development

“…To date three members of the family have been identified in mammals: tenascin-C (TN-C), tenascin-R (TN-R), and tenascin-X (TN-X). TN-C, variably identified as myotendinous antigen (Chiquet and Fambrough, 1984), GMEM (Bourdon et al, 1985), cytotactin (Grumet et al, 1985), J1 (Kruse et al, 1985), hexabrachion (Erickson and Iglesias, 1984), or simply tenascin, is the prototype of this gene family. TN-C has widespread developmental expression and a variety of postulated morphogenetic functions (Chiquet-Ehrismann et al, 1986;Ruegg et al, 1989;Crossin and Hoffman, 1991;Tan et al, 1991;Julian et al, 1994;Young et al, 1994).…”

Purification and partial characterization of Xenophus laevis tenascin from the XTC cell line

“…Originally described in the chicken as myotendinous antigen [5,6], tenascin is identical or homologous to molecules discovered simultaneously by ,3thor laboratories: cytotactin in the chicken [7][8][9] ;.nd glioma mesenchymal extracellular matrix protein in human [10], It appears furthermore that tenascin is the predominant mouse component recognized by the Jt antibody [11].…”

“…Electron microscopy studies have shown that tenascin has a six-armed structure with a central core named hexabrachion [9il [2][3][4][5][6][7][8][9][10][11][12][13][14]. The complete sequence of chicken tonE.seth [15][16][17][18] as well as part of that of human tenascin [19] have been determined.…”

“…The latter can undergo alternative splicings giving rise to various molecular forms which have different patterns of expression [18][19][20]. Tenascin affects differently the adhesion of" various cell types [7,[21][22][23][24] and inhibits the attachment of cells to FN substrates [24][25][26]. Using fusion proteins containing different regions of the molecule it has been shown that tenascin contains both cell binding sites and sequences with antiadhesive effects [18] providing a possible interpreta.…”

Characterization of a monoclonal antibody directed against a sulphoglycolipid that is evolutionarily conserved and developmentally regulated in rat brain

“…The HNK-1 epitope has been shown to be present in various other glycoproteins, many of which are known to be involved in adhesive phenomena among neural cells. Among these are the neural cell adhesion molecules N-CAM (Kruse et al 1984), cytotactin (Grumet et al 1985), L1, L2, and Jl (Rathjen and Schachner 1984;Kruse et al 1985), and the myelinassociated glycoprotein (Poltorak et al 1987). In fish, the epitope has been shown to be present in a group of glycoproteins, called ependymins, that are secreted into the cerebrospinal fluid of goldfish during learning (Shashoua et al 1986) and in a subset of acetylcholinesterase molecules present in the electric organ of Electrophorus and Torpedo spp.…”